This communication describes a new method of cooling of planar Very Large Scale Integrated (VLSI) circuits which allows one to obtain chip heat fluxes in excess of 500 W/cm 2 with acceptable temperature rises. It is shown that by scaling impinging fluid Jet heat transfer technology to small geometrical dimensions, and by using water as the coolant, a hiSh-performance cooling system can be designed. The convective heat transfer coefficients obtained in this method are significantly greater than that obtained in the conventional liquid cooling technology used for mlcroelectronic devices, including the immersion cooling.
The method lends itself to control of non-uniformitles in the temperature field which could result from uneven heat dissipations in the integrated circuit elements.
Experimental verification of predictions of the present analysis is planned.
Implementation of Very Large
Scale Inte~ated (VLSI) microelectronlcs in the new electronic devices will involve such high heat dissipation density levels that will challenge design engineers for offering innovative solutions to critlcal thermal control problems. An excellent survey of thermal control applications in the design and packaging of microeleotronlc equipment is given in a recent paper [i]. Authors of this reference indicated that although current product development goals are routinely based on Integrated chip (IC) heat fluxes of 2-3 W/em 2, R&D target values are already in excess of 100 W/cm 2. These fluxes must be achieved with chip surface temperatures in the range of 100-125Β°C. In addition, reliabillty of mlcroelectronic devices requires the near elimination of all spatial temperature variations. According to [2] the component reliability decreases by i0 percent for every 2Β°C temperature rise. Consequently, the thermal package designer of microelectronlc 517 518 A.M. Kiper Vol. II, No. 6 equipment is devoting considerable effort toward the development of advanced thermal control techniques. Leadless ceramic chip carriers (LC-3s) are expected to find increasing use in the next generation of microcircuits. Even though (LC-3s) offer great advantages in improving the capabilities of future electronic devices, the heat dissipation rates involved in such applications require thermal control techniques that are not in general use at this time. The high heat fluxes and low junction-to-ambient temperature differences necessary for VLSI microelectronic packaging appear to make forced-alr convection cooling extremely difficult. Consequently, at the present time, the computer industry is gradually changing over from forced-air to liquid cooling. Although formerly only Cray Research